Lesson Notes By Weeks and Term - Senior Secondary 2

Data modelling I

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  4. Data modelling I

Term: 1st Term

Week: 3

Class: Senior Secondary School 2

Age: 16 years

Duration: 40 minutes of 2 periods each

Date:       

Subject:      Data Processing

Topic:-       Data Modeling I

SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to

  1. Discuss all the types of data modeling

INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers, demonstration, videos from source

INSTRUCTIONAL MATERIALS: Videos, loud speaker, pictures, Data Processing for senior Secondary Education by Hiit Plc, WAPB Computer Studies for Senior Secondary I by Adekunle et al, On-line Materials.

INSTRUCTIONAL PROCEDURES

PERIOD 1-2

PRESENTATION

TEACHER’S ACTIVITY

STUDENT’S ACTIVITY

STEP 1

INTRODUCTION

The teacher reviews the previous lesson on levels of abstraction in data modeling

Students pay attention

STEP 2

EXPLANATION

He explains the ER, Hierarchical and Network models

 

Students pay attention and participates

STEP 3

DEMONSTRATION

He further explains the relational, object-oriented and object-relational database model

Students pay attention and participate

STEP 4

NOTE TAKING

The teacher writes a summarized note on the board

The students copy the note in their books

 

NOTE

TYPES OF DATA MODELING

  1. ER (Entity-Relationship) Model

       

This model is based on the notion of real-world entities and relationships

among them. It creates an entity set, relationship set, general attributes, and

constraints.

Here, an entity is a real-world object; for instance, an employee is an entity

in an employee database. An attribute is a property with value, and entity

sets share attributes of identical value. Finally, there is the relationship

between entities.

 

  1. Hierarchical Model

       

This data model arranges the data in the form of a tree with one root, to

which other data is connected. The hierarchy begins with the root and

extends like a tree. This model effectively explains several real-time

relationships with a single one-to-many relationship between two different

kinds of data.

For example, one supermarket can have different departments and many

aisles. Thus, the ‘root’ node supermarket will have two ‘child’ nodes of

(1) Pantry

(2) Packaged Food.

 

  1. Network Model

       

This database model enables many-to-many relationships among

The connected nodes. The data is arranged in a graph-like

structure, and here ‘child’ nodes can have multiple ‘parent’ nodes.

The parent nodes are known as owners, and the child nodes are

called members.

 

  1. Relational Model

Relational database is a type of database or database

management system that stores information in tables—rows and

columns of data—and conducts searches by using data in

specified columns of one table to find additional data in another

table. In a relational database, the rows of a table represent

records (collections of information about separate items) and the

columns represent fields (particular attributes of a record). In

conducting searches, a relational database matches information

from a field in one table with information in a corresponding field

of another table to produce a third table that combines requested

data from both tables.

Car Number

PS1002 LAG

Name:

Sammy King

Address:

12 Abu Road, Lagos

 

This data is in the traffic office data base which shows all the cars

registered in the city of Lagos. A row resembles a table showing

the car number, name and address of the owner. Since no two

cars have the same number, the car

 

number field is unique and it is called a key field. If the owner of the car

commits an offence like over speeding or packing at an unauthorized place,

the police can use his car number to trace him and subsequently prosecute

him.

The most valuable feature of relational databases is that entries can be

easily added, deleted and modified.

 

  1. Object-Oriented Database Model

       

This data model defines a database as an object collection, or recyclable

software components, with related methods and features.

For instance, architectural and engineering real-time systems used in 3D

modeling use this data modeling process. 

 

  1. Object-Relational Model

       

This model is a combination of an object-oriented database model and a

relational database model. Therefore, it blends the advanced functionalities

of the object-oriented model with the ease of the relational data model.

The data modeling process helps organizations to become more data

driven. This starts with cleaning and modeling data.

.

EVALUATION:    1. Explain all the types of data modeling

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively